It is hard for people to accept change, but change is one of the few things that is inevitable. No matter how much people want their favorite hunting or fishing spot to stay the same, things will happen that will make it different both on the ground and in your mind. This concept has been understood since around 500 BC when Heraclitus said, “No man ever steps in the same river twice, for it’s not the same river and he’s not the same man.” When it comes to the forests, fields, streams, mountains and lakes that many of us care about, change can be hard to accept. Finding more hunters, a change in regulations or the presence of a new road in our secret spot can sour one’s mood.
With summer air temperatures rising and wildland vegetation drying, the region’s tool for landscape change, fires, will again become apparent. Fires can cause fish and wildlife habitats to be renewed, maintained, or degraded. The exact effects depend on fire intensity and location. The lodgepole pine forests found in the surrounding mountains will only persist if they are occasionally burned. This species has serotinous cones that produce seeds after they are scorched so fires are necessary to renew these ecosystems. A fire in the ponderosa pine forests of southern Utah has a different effect. These areas need fires to reduce fuels so older pine forest can be maintained. Then there are the old-growth spruce forests of the Pacific Northwest that burn once a millennium. When these forests burn, habitat quality for rare old-growth species like marbled murrelets and American pine martens are degraded.
Although fire can have varying effect depending upon the forest type, the open areas left behind will result in a pulse of growth that attracts many new species. Some of the new visitors are favored by hunters, such as elk, chukar and ruffed grouse.
The effects of fire are not always positive, though. For example, sage grouse populations have been showed to decline following fires. This is because burns reduce sagebrush cover and is replaced by the flammable non-native grass species cheat grass.
Fires also can cause changes to streams. In locations where thunderstorms and floods occur in an area recently scorched by a high intensity fire, streams can torrent in a manner that eliminates fish and reduces the quality of their habitat. By contrast, in watersheds where a fire has burned less intensely, flames can kill individual trees which eventually fall into the stream increasing habitat complexity and fish numbers.
Not all disturbance is driven by abiotic mechanisms. Some is driven by biota other than humans.
A good example of this is the ecosystem engineer known as a beaver. Over the last several years these animals have been expanding their range on public lands across the west. In the Logan River Watershed, there are two or three times more beaver dams now than there was a decade ago. These ponds can increase fish production and improve access for anglers.
Another setting where biotic disturbance has been shown to be important is around springs. Historically, large mammals and humans caused sufficient vegetative disturbance near springs that they maintained and area of open water. To keep cattle from turning these areas into muddy bogs, many larger springs on public lands have been fenced. This often resulted in vegetation covering the water’s surface making them less valuable to native fish and amphibian species. These situations are much like those faced by Goldilocks: some disturbance is good but too much puts natural processes at risk.
The big difference between human and natural disturbance is humans cause press disturbance while natural disturbance is often pulsed. A good example of a press disturbance is a housing development in deer winter range. Once houses are built, habitat for deer is potentially reduced forever. A fire, instead, is a pulsed disturbance. Yes, burns do affect an area for a couple years or a few decades, but eventually historic conditions will return. Natural disturbance therefor fosters a mosaic of habitat conditions for fish and wildlife to live out their lives.
So why should hunters or anglers care about change? Because success is determined by how one adapts to these changes. Most duck hunters are aware that wind direction should determine how and where to set out duck decoys. But hunters and anglers often don’t foster a similar understanding of how disturbance, whether it is fire or floods, alter animal behavior. The ability to respond to these landscape scale changes is an attribute that is required if you want to be a successful outdoorsman over a lifetime.